Frothing agents for use in froth flotation processes



Patented Apr. 1, 1952 FROTHING AGENTS FOR USE IN FROTH FLOTATION PROCESSES Roger F. Powell, Gwelo, Southern Rhodesia, and

Herbert Muggleton Stanley, Tadworth, England No Drawing. Application October 12, 1949, Serial No. 121,054 In the Union of South Africa, August 17, 1948 6 Claims. 1

This application is a continuation-in-part of our application Serial Number 112,842 filed on 27th August 1949, now abandoned.

This invention relates to froth flotation processes for the concentration of materials amenable to such processes, including the noble and base metal ores and their products, the non-metallic ores, coal and valueless materials which are selectively floated from valuable materials, in which processes iroths are produced by the addition of frothing agents to the flotation pulp.

The invention consists in a process or processes utilising frothing agents in the same manner and for the same purpose as steam-distilled pine oil, but which by their nature need to be used in substantially smaller quantities than pine oil in order to produce closely similar results.

According to the invention in a froth flotation process, in addition to well-known promoting and collecting agents such as the xanthates et cetera there is present as frothing agent a tetra-alkoxyparafiln having from two to five carbon atoms in the parafiin chain, a pair of alkoxy radicalsalkoxy being limited to methoxy, ethoxy, normal propoxy, or isopropoxy being attached (by the carbon-oXygen-carbon at ether linkage) to; each terminal carbon atom of the chain. In any such tetra-alkoxy-paraffin the two pairs of alkoxy radicals need not necessarily be, though they may be, the same; for instance a pair of ethoxy radicals may be attached to one carbon atom and a pair of isopropoxy radicals attached to the other or another carbon atom, or there may be two pairs of ethoxy radicals or any similar combination of the four alkoxy radicals methoxy, ethoxy, normal propoxy, and isopropoxy.

The following examples serve to make quite plain the scope of the generalised structure described above:

Ercample 1 1:1. 2: 2 tetraethoxy-ethane Example 2 1 :1, 4 4 tetramethoxy-butane H OCH:

OCH:

Eat-H 10 O CH:

Example 3 15 1 1 ethoxy-4 4 isopropoxy-butane 00in, l/

O.CH(CH|)2 O.CH(CHs)2 H Carefully standardised laboratory flotation tests were carried out in a 2000-gram Denver- Fahrenwald fixed-speed flotation machine without the addition of any air other than that sucked in in the normal manner. Two different ores, each from a different mine, were tested: in each the valuable minerals to be floated were chalcopyrite and pyrrhotite, the latter only being auriferous. The two ores differed in the percentages of these minerals present, in their natural pH after grinding, and in the amount of deleterious colloidal material present. On each ore there was first done a control test using as frother commercial triethoxybutane, whose properties have been established as superior to steam-distilled pine oil on several large wellknown ore concentrators for several years.

45 PROCEDURE ON FIRST ORE 2000 grams of moist ore was ground for 50 minutes in a ballmill with 1200 cubic centimeters of tap-water and 1.2 grams of copper-sulphate.

50 Pulp was washed out and made up to standard 3 volume in a 2000-gram Denver-Fahrenwald flotation machine.

0.10 grams of sodium-isopropyl-xanthate was then added to the pulp plus one drop from a standardised capillary tube, of the substance being tested as frother (each drop found by measurement to be approximately 0.0135 00.). After 30 seconds the suction-air valve was opened, and a primary concentrate collected for exactly one hundred and twenty seconds. Suction-air valve was closed and another 0.25 grams of the xanthate added, plus 4 standardised capillary drops of the frother. Suction-air valve was opened, and froths allowed to run over the lip of the machine for 5 minutes, with a standard stream of water being meanwhile added to'the;

' capillary drops of the frother; suction air valve was opened, and froths allowed to run over the lip-of -them'achine for 5 minutes, with a standard pulp at the back of the machine. This constitutes the secondary concentrates. Suction-air valve was then closed, bottom plug was opened, and the tailings (residue) pulp washed out into a bucket. Primary concentrates, secondary concentrates, and tailings (residue) werefiltered dried at 100 cent, and analysed. 1 The pH of the tailings pulp was found to be 7 approximately 9.2, the pulp being well-flocculatedand the degree of grinding being approximately 62% minus 200-mesh.;

PROCEDURE -ON SECOND ORE 2000 grams of moist ore was ground for 35 minutes in a ballmill with 1200 cubic centimeters of tapwater. The pulp was washed out stream of water being added to the pulp at the back of the machine. This constitutes the secondary concentrate. Suction-air valve was closed, bottom plug opened, and the tailings v(residue) pulp washed out into a bucket. Primary concentrates, secondary concentrates, and tail-ings (residue) were filtered, dried at 110 cent. and analysed.

The pH of the tailings pulp was found to be approximately 8.0 and "the degree of grinding approximately 8il% minus 100-mesh Evenja'fter long standing} the "water in the tailings lll was very colloid-y. This "particular ore notoriously gave rather low recoveries er the pyrrhotite,

whatever 'frother was used (including pine oil).

The results'of the testswere a's: "follows: 1

FIRST ORE Lbs. Valuable Mineral in Product Perg r t of Substance tested as Prgduct centage ig Percent Percent Percent Ch 10 I A Valueless 2 .391 Pyrrhotitc Gangue 1 i a 1st Ccnc 8. 17 70. 1 63. Control Test:l:1:3 'Irieth- 2nd Cone 6.71 6.0 85.6 oxybutane Commercial. Combined Gone. 14. 88 76.1 149.1 Res new- 85.12 2.4 l 33. 5 Calculated 0re 100 78.5 182.6 1st Conc 7.44 67.3 58.9 lzlz2z2zTetraethoxyethane 2nd Cone 7.09 5. 9 90. 9 Combined 0on0. 14. 53 r 73.2 149. 8 Resldue 8547 1.2 26.4 Calculated Ore 100 74.4 176.2 1st Conc 9. 87 62. 2 88. 2 l:1:2:2:lotraisopropoxy- 2nd Conc 11.23 9.3 78.6 ethane Combined C0nc 21. 71. 5 166. 8 Residue 78. 9O 2. 2 g 15. 0 Calculated Ore 100 73. 7 181.8 1st Conc 9.18 69.1 76.6 l:l:2:2:Tetra-n-Propoxy- 7. 22 4.6 79.6 ethane c 16. 40 73. 7 156. 2 Residue 83. 2.0 28. 5 Calculated Ore Y 75.7 184.7

SECOND O'RE TESTED [From a difierent mine, but containing the same 2 minerals, indifierent proportions] v n Lbs. Valuable Mineral V Product f qi igff Der ton of (Dre f Substance tested as centage Product 1 7 I Weg l f 1 ent Percent Perc n Ch 1 -Oha-lcoyrrho- Valueless fi Pyrrhotite, pyrite tite Gangue n e V 1stConc.. 2.78 18.8 53.1" 28.0 10.5 29.6 7 New Control Test 1:123 2d Conc 5.47 1.9 59.8 38.3 2-1 65.4 Triethoxybutane Com- Combined Cone. 8.25 12.6 95.0 mercial. Residue 91.76 0.7 59.9 7 Oalculated 'Ore. 100 13.3 154.9 st o n nn nn 4.87 11.2 46.7 n 0110;. 6. 4 2.4 71.9 1 1 Tetraethmypw' Combined 0on0. 11.01 13. 0 118.6 Pan I Res 1due. 88.99 1.2 36.8 I, Calculated Ore 100 14.8 155.3 5312106211; 11. 0 47. 3 .onc 1.0 57.3 ag- Tetlaethlxypen' Combined Cone. 9. 02 12.0 104.6 Residue-.44... 90.98 .10 1.9 33.7 Calculated Ore 100 .69. 13.9 138.3

Norm-Such a powerful Frotherthat only hall the standard quantities used. V

We claim:

1. A process of concentrating material comprising subjecting the material to froth flotation in the presence of a collecting agent and a frothing agent consisting essentially of a tetraalkoxy parafiin having in the paraffin chain from two to five carbon atoms, a pair of alkoxy radicals selected from the group methoxy, ethoxy, normal propoxy and iso-propoxy being attached to each terminal carbon atom in the chain.

2. A process of concentrating material comprising subjecting the material to froth flotation in the presence of a collecting agent and a frothing agent consisting of a bisacetal of ethane. propane, butane and pentane.

3. The process claimed in claim 1 in which the frothing agent is tetra-ethoxy-ethane.

6 4. The process claimed in claim 1 in which the frothing agent is tetra-ethoxy-propane.

5. The process claimed in claim 1 in which the frothing agent is tetra-ethoxy-pentane.

6. The process claimed in claim 2 in which the frothing agent is tetra-ethoxy-butane.

ROGER F. POWELL. HERBERT MUGGLETON STANLEY.

REFERENCES CITED The following references are of record in the file of this patent:

Richters Organic Chemistry, second English edition, formulated by Percy E. Spielman, published by P. Blakistons Son & Co., 10l2 Walnut St., Philadelphia, Pa., vol. 1, pages 346-348. 

1. A PROCESS OF CONCENTRATING MATERIAL COMPRISING SUBJECTING THE MATERIAL TO FROTH FLOTATION IN THE PRESENCE OF A COLLECTING AGENT AND A FROTHING AGENT CONSISTING ESSENTIALLY OF A TETRAALKOXY PARAFFIN HAVING IN THE PARAFFIN CHAIN FROM TWO TO FIVE CARBON ATOMS, A PAIR OF ALKOXY RADICALS SELECTED FROM THE GROUP METHOXY, ETHYOXY, NORMAL PROPOXY AND ISO-PROPOXY BEING ATTACHED TO EACH TERMINAL CARBON ATOM IN THE CHAIN. 